It would be nice, but there's nothing that lets you use a non-XF template/style like that within the XF styling system. I've always loved the MVP Ready style/framework (or whatever you want to call it).
In my dream world, XenForo would license MVP Ready for the $525 "redistribution license", then cut it all up and use it's various components in XF... Make the general XenForo 2.0 look/feel based on it. You would end up with not only a really nice style, but also some useful components...
https://jumpstartthemes.com/demo/v/2.0/templates/admin/components-charts.html
https://jumpstartthemes.com/demo/v/2.0/templates/admin/index.html
Could get rid of jQuery Tools (which updates are sporadic at best) for things like tooltips, popovers and tabs:
https://jumpstartthemes.com/demo/v/2.0/templates/admin/components-tabs.html
https://jumpstartthemes.com/demo/v/2.0/templates/admin/components-popups.html
You get a few nifty form input items (auto-tokenization and multi-value selections for example):
https://jumpstartthemes.com/demo/v/2.0/templates/admin/form-plugins.html
But yeah... that's my dream...